1. Field of the Invention
The invention concerns a holder for holding a carrier where the holder is inserted into a cylindrical well, for example, into a multiwell plate. In addition the invention relates to a multiwell plate with this type of holder.
2. Brief Discussion of the Related Art
This kind of holder in inserted in the recesses or wells of titration and/or filtration plates and serves for the positioning of a carrier at a specified height above the bottom of the wells.
Multiwell plates, for example, plates with 96 wells, are a proven device in biomedical research, analytical chemistry and clinical diagnosis and are standard technology. There is a wide range of variants of classic multiwell plates. While the classical variant is primarily used for parallel support and handling of liquids and reaction solutions, there are variants of multiwell plates for special analytical needs, e.g. the standard filtration plate for cleaning fluids with built-in filters in the base. There are also specific variants such as the use of a double plate for the cultivation of membrane cell cultures
For chemical-analytical measurement methods which are also used in miniaturised form in modern research in the fields of genomics, proteomics and metabolomics, one sometimes needs very complex constructions. This kind of construction is described below. In metabolomics, one treis to analyse large sections of the metaboloms, i.e. the totality of the natural metabolites occurring in an organism, as efficiently as possible from very small sample volumes, wherein several steps are involved in handling the sample. The usual multiwell plate format as used in life sciences is employed. This requires additional functionality in the wells of the multiwell plate. This can be e.g. an additional base in form of a fleece disc which, inter alia, can serve as a reaction site, as a reservoir for chemicals or for an immobilisation site.
Multiwell plates have been used for many years as a standard utensil in biomedical and chemical research either for the simple presentation or handling of liquid volumes in a highly parallel manner or for the performance of reactions, cleaning, extractions and substance identification. An overview of the many applications of such plates is provided in the catalogues of relevant manufacturers such as PALL, Millipore, Costar, Nunc, Whatman and many more.
In addition, wells are also used as a quasi reaction cell with lower outlet and are described, for example, in W0/1992/002303A1. Further it is possible to combine several reaction or extraction processes by the combination of several multi-well plates as described, for example, in WO/1999/019067A1.
A further development is represented by the integration of tools and structures in the wells of the multiwell plates. This includes both the fixed installation of filters (WO/2000/066268A2) as well as the use of a second plate with wells having a smaller diameter in order to produce a double-walled structure and thus compartmentalisation into two reaction sites as described in (WO/2002/102965A2).
When positioning a carrier in a well, e.g. a filter or fleece disc, it is necessary to prevent the carrier from falling out of the holder or out of the well. In addition, some applications require that the carrier be placed into a gase or liquid charged into the well.
U.S. Pat. No. 5,208,161 describes a cylindrical holder at the bottom of which is a lattice-like insert. In the upper part of the cylindrical insert is a circular ring which prevents a carrier from sliding out.
EP 0 834 729 A2 describes a multi-piece cylindrical insert with a lower part having a cylindrical wall from which project supporting elements with holding projections in the inner area. A filter disc is laid on the supporting elements and is fixed in position by means of an upper insert which is inserted into the lower insert.
DE 698 31 408 A2 describes a filter plate for connecting several filter holding elements in a matrix. Each filter holding element has holding spigots at its lower part and between which wells are arranged.
U.S. Pat. No. 4,125,426 shows an insert for a laboratory plate, wherein a holding plate is connected via a rod with a circular gripping piece which abuts a well at the top of the laboratory plate. The gripping piece serves as an aid to movement.
DE 691 09 651T2 shows a cylindrical cell culture insert at the upper edge of which there are surfaces facing outwards with a well at the top for the support.